As is well known, various types of probe apparatus are widely used in inspecting liquid crystal panels and the like (hereinafter referred to as substrates under inspection).
One example of conventional apparatus will be described with reference to FIGS. 9 and 10. FIG. 9 is a front view of such a conventional probe apparatus in an inspecting situation, and FIG. 10 is a plan view thereof.
This probe apparatus comprises an inspecting device 10, an intermediate substrate 3 and a probe substrate 4. The inspecting device 10 is electrically connected to a proximal end e1 of the intermediate substrate 3. The intermediate substrate 3 has a distal end e2 electrically connected to a proximal end b1 of the probe substrate 4. The probe substrate 4 has a distal end b2 electrically connectable to a substrate 11 under inspection. The inspecting device 10 includes TAB (Tape Automate bonding) packages 2, a control substrate 1, and a signal generator 9. The signal generator 9 is electrically connected to the control substrate 1 through a signal transmission line 12. The control substrate 1 is electrically connected to proximal ends c2 of the TAB packages 2. The TAB packages 2 have distal ends c1 electrically connected to the proximal end e1 of the intermediate substrate 3.
Each of the control substrate 1, intermediate substrate 3 and probe substrate 4 has an elongated rectangular shape. A plurality of TAB packages 2 are arranged at predetermined intervals between the control substrate 1 and the intermediate substrate 3.
The probe substrate 4 has a plurality of inspecting terminals 4a juxtaposed at micro intervals, e.g. of 50 μm. The inspecting terminals 4a have distal ends thereof precisely positioned relative to a plurality of pads formed on the substrate 11 under inspection. The inspecting terminals and pads are placed in pressure contact to be conductive with each other, thereby allowing a predetermined inspection to be carried out.
However, each inspecting terminal 4a has a minute width, e.g. of 20 μm, and thus is prone to damage when the probe substrate 4 is pressed by a pressure head to place the inspecting terminals 4a in pressure contact with the pads of the substrate 11 under inspection. In addition, it is necessary to replace the entire probe substrate 4 with a new substrate, due to its elongated one-piece formation, even when one of the inspecting terminals 4a becomes defective because of disconnection or the like. Such a replacement is costly while amounting to a poor yield, which results in an economic disadvantage.
Generally, the above probe apparatus has “the probe substrate 4 and the intermediate substrate 3” and “the intermediate substrate 3 and the TAB packages 2” joined, through an ACF (Anisotropic Conductive Film), respectively, and “the TAB packages 2 and the control substrate 1” joined by solder. Thus, the probe substrate 4 formed of polymer resin film is easily deformable under the influences of heat, stress and the like. As a result, the more the probe substrate is elongated, the more often the intervals become irregular between the inspecting terminals 4a, which impedes improvement in the accuracy of terminal patterns. Even if the probe apparatus may be manufactured with high precision, some disadvantages remain in that the intervals between the inspecting terminals 4a are likely to become irregular due to subsequent changes in environmental conditions, and that the probe substrate 4 has a relatively short life (i.e. a period over which a high precision condition can be maintained).
Further, due to the above-described disadvantages, it is difficult to maintain a precise registration between the numeral inspecting terminals 4a and the pads of the substrate 11 under inspection in a constant state during an inspection. This hampers a stable inspection.
The present invention has been made having regard to the drawbacks noted above, and its primary object is to provide a probe apparatus for enabling an economic replacement by a new probe substrate in the event of a defect such as a disconnection.
A second object of the invention is to provide a durable probe apparatus which is manufactured with a reduced irregularity in the intervals of inspecting terminals of a probe substrate to enhance the accuracy of terminal patterns, and which maintains such accuracy over a long period after its manufacture.
A third object of the invention is to provide a method of effecting a stable inspection using such a probe apparatus.